1. Field of the Invention
The present invention relates to a belt bushing for safety belt and an assembling method thereof, and more particularly, to a belt bushing for safety belt added to a belt combiner combining a safety belt and increasing a tensile strength of the safety belt, preventing belt cutting, and reducing a manufacturing cost of the belt combiner, and an assembling method thereof.
2. Description of the Related Art
In general, a safety belt is to firmly support a human body to prevent injury as well as keep life. Particularly, of much significance is a combination structure of such as a variety of belt combiners combining a belt, that is, a belt combiner for safety device, a belt combiner firmly fixed to a car frame, and a belt combiner for buckle.
This will be described for example. A safety belt 20 for vehicle is wound at both sides in through-holes 11 of belt combiners 10, respectively, and is firmly combined and supported by sewing, etc.
However, the belt combiner 10 is formed to have more than a predetermined strength and be thin to the maximum in consideration of material limitation and cost saving and winds and combines the safety belt 20.
Thus, if being repeatedly applied to the combined safety belt 20, a spontaneous tensile pressure is transmitted to an end of the belt combiner 10 of a thin plate shape as it is. The end of the belt combiner 10 serves as an edge of a knife and thus, does damage to the wound safety belt 20 by a little. The safety belt 20 may not guarantee safety because it does not withstand a pressure of about 1,600 kgf/cm2 or more and thus is cut.
Therefore, in order to fix the defects, the belt combiner 10 should be thickened to thereby increase a curvature radius for winding the safety belt 20 and increase a tensile pressure. However, the belt combiner 10 cannot be recklessly thickened because of a thickness limitation of material as above.
In recent years, a separate belt bushing 30 shown in FIGS. 1 to 3 is manufactured and fitted into the through-hole 11 of the belt combiner 10 to wind the safety belt 20. By doing so, a curvature radius of the wound safety belt 20 increases, a tensile pressure applied to the safety belt 20 is decentralized, and a concern about a damage of the safety belt 20 is reduced.
The belt bushing 30 includes a reinforcement 31, reinforcement supports 32, and a combination groove 33. The reinforcement 31 is formed in a straight-line shape and get in contact with a frame of the through-hole 11 of the belt combiner 10 at the side of which the safety belt 20 is wound. The reinforcement supports 32 are bent outward at upper and lower ends of the reinforcement 31 and form an approximately  shape with the reinforcement 31. The combination groove 33 is provided between the reinforcement 31 and the reinforcement support 32.
The belt bushing 30 and the belt combiner 10 each are manufactured separately and are conveyed for each assembly process. The frame of the through-hole 11 of the belt combiner 10 is inserted into the combination groove 33 of the belt bushing 30 to combine the safety belt 20. By doing so, the reinforcement 31 gets in contact with an inner surface of the through-hole 11, and the reinforcement supports 32 get in contact with one-side upper and lower surfaces of the belt combiner 10.
By winding the safety belt 20 at the side of the reinforcement 31 of the belt bushing 30, the curvature radius of the safety belt 20 is increased, the tensile pressure applied to the safety belt 20 is decentralized by the belt bushing 30, and the concern about safety belt 20 cutting caused by the belt combiner 10 is reduced.
However, the belt bushing 30 and the belt combiner 10 each are manufactured, processed in painting and coating processes, and kept in safe in a separate way as well as they each are conveyed for assembly process in a separate way to fit the belt bushing 30 into the through-hole 11 of the belt combiner 10. Therefore, many manufacturing processes and long time are required and a unit cost increases.
Even in assembly, it happens that the belt bushing 30 is released from the belt combiner 10 when the safety belt 20 is wound in the belt bushing 30 after the small-size belt bushing 30 is fitted into the through-hole of the belt combiner 10. This deteriorates workability, increases a time for work by an unskilled worker, and causes a difficulty in assembling the belt bushing 30 by a non-manual work.
Even after completion of the assembly of the belt bushing 30, spacing is generated and collision and noise are caused between the belt bushing 30 and the through-hole 11 of the belt combiner 10 because of a motion of the wound safety belt 20.